Force limiting mechanism for medical instrument

ABSTRACT

A surgical clip applier and methods for applying surgical clips to a vessel, duct, shunt, etc., during a surgical procedure are provided. In one exemplary embodiment, a surgical clip applier is provided having a housing with a trigger movably coupled thereto and an elongate shaft extending therefrom with opposed jaws formed on a distal end thereof. The trigger is adapted to advance a clip to position the clip between the jaws, and to move the jaws from an open position to a closed position to crimp the clip positioned therebetween.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/907,764 filed Apr. 14, 2005, now issued as U.S. Pat. No. 7,288,098 onOct. 30, 2007, and entitled “Force Limiting Mechanism for MedicalInstrument,” which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates broadly to surgical devices, and inparticular to methods and devices for applying surgical clips to ducts,vessels, shunts, etc.

BACKGROUND OF THE INVENTION

In recent years surgery has markedly advanced through the performance oflaparoscopic and endoscopic surgical procedures such ascholecystectomies, gastrostomies, appendectomies, and hernia repair.These procedures are accomplished through a trocar assembly, which is asurgical instrument used to puncture a body cavity. The trocar typicallycontains a sharpened obturator tip and a trocar tube or cannula. Thetrocar cannula is inserted into the skin to access the body cavity, byusing the obturator tip to penetrate the skin. After penetration, theobturator is removed and the trocar cannula remains in the body. It isthrough this cannula that surgical instruments are placed.

One surgical instrument that is commonly used with a trocar cannula is asurgical clip applier for ligating a blood vessel, a duct, shunt, or aportion of body tissue during surgery. Most clip appliers typically havea handle with an elongate shaft having a pair of movable opposed jawsformed on an end thereof for holding and forming a ligation cliptherebetween. The jaws are positioned around the vessel or duct, and theclip is crushed or formed on the vessel by the closing of the jaws.

In many of the prior art clip appliers, the feeding and formingmechanisms require precise timing and coordinated movement of componentsto operate. This need for precise timing and control has resulted in theneed for complex mechanical designs, thereby increasing the cost of theclip appliers. Many prior art clip appliers also use a spring-loadedclip advancing assembly to advance one or more clips through the shaftof the device. As a result, the jaws must contain a mechanism forpreventing accidental projection of the clip from the device before theclip is formed. Other drawbacks of current clip appliers include theinability to handle an overload applied to the jaws by the trigger undera variety of conditions. Many devices require full closure of the jaws,which can result in overload on the jaws when the vessel or ductpositioned therebetween is too large to allow full closure, or when aforeign object is positioned between the jaws.

Accordingly, there remains a need for improved methods and devices forapplying surgical clips to vessels, ducts, shunts, etc.

SUMMARY OF THE INVENTION

The present invention provides method and devices for applying asurgical clip to a vessel, duct, shunt, etc. In one exemplaryembodiment, a surgical clip applier is provided having a housing with atrigger movably coupled thereto and an elongate shaft extendingtherefrom with opposed jaws formed on a distal end thereof. The triggeris adapted to advance a clip to position the clip between the jaws, andto move the jaws from an open position to a closed position to crimp theclip positioned therebetween.

The surgical clip applier can have a variety of configurations, and itcan include a variety of features to facilitate advancement andformation of a surgical clip. In one embodiment, the surgical clipapplier can include a feeder shoe that is slidably disposed within theelongate shaft and that is adapted to drive at least one surgical clipthrough the elongate shaft. In an exemplary embodiment, the feeder shoecan be adapted to move only in a distal direction, such that proximalmovement of the feeder shoe is substantially prevented. The elongateshaft can also include a clip track disposed therein and adapted to seatat least one surgical clip. The feeder shoe can be slidably disposedwithin the clip track.

A variety of techniques can be used to facilitate distal movement andprevent proximal movement of the feeder shoe. In one exemplaryembodiment, the feeder shoe can include a tang adapted to engage theclip track to prevent proximal movement of the feeder shoe within theclip track, yet allow distal movement of the feeder shoe within the cliptrack. The clip track can include several openings formed therein forreceiving the tang to prevent proximal movement of the feeder shoewithin the clip track. In another exemplary embodiment, the feeder shoecan include a tang and the feed bar can include several detents formedtherein and adapted to engage the tang to move the feeder shoe distallywhen the feed bar is moved distally.

In another embodiment, the elongate shaft can include a feed barslidably disposed therein and coupled to the trigger such that movementof the trigger toward a closed position is adapted to advance the feedbar distally thereby advancing the feeder shoe distally. By way ofnon-limiting example, the feed bar can be coupled to the trigger by atrigger insert that is mated to the trigger, and by a link that extendsbetween the trigger insert and the proximal end of the feed bar. Theproximal end of the feed bar can include a coupler that is adapted toreceive a portion of the link. The feed bar can also include a distalend having an advancer that is adapted to engage a distal-most clip andto drive the distal-most clip into the jaws. In certain exemplaryembodiments, the feed bar can be adapted to engage and initiateadvancement of a distal-most clip into the jaws prior to initiatingadvancement of the feeder shoe.

In another embodiment, a clip advancing assembly for advancing a clipthrough a surgical clip applier is provided. The clip advancing assemblycan be used with a variety of surgical clip appliers, including thoseknown in the art. In one exemplary embodiment, the clip advancingassembly can include a clip track that is adapted to seat at least oneclip, and a feeder shoe that is adapted to slidably mate to the cliptrack and to move in a distal direction to move at least one clipdisposed within the clip track in a distal direction. The feeder shoecan include, in one exemplary embodiment, a tang that is adapted toengage the clip track to prevent proximal movement of the feeder shoewithin the clip track, and that is adapted to allow distal movement ofthe feeder shoe within the clip track. The clip track can include aplurality of openings formed therein for receiving the tang to preventproximal movement of the feeder shoe within the clip track.

The clip advancing assembly can also include a feed bar that is adaptedto couple to a movable trigger formed on a housing of a surgical clipapplier and that is adapted to slidably move distally when the triggeris closed to advance the feeder shoe and at least one clip disposedwithin the clip track. The feed bar can have a variety ofconfigurations, and in one exemplary embodiment the distal end of thefeed bar can include an advancer that is adapted to engage a distal-mostclip to drive the distal-most clip from the clip track into jaws formedon a distal end of a surgical clip applier. In another exemplaryembodiment, the feeder shoe can include a tang, and the feed bar caninclude a plurality of detents formed therein that are adapted to engagethe tang to move the feeder shoe distally when the feed bar is moveddistally. In use, the proximal end of the feed bar can include a couplerthat is adapted to receive a link for coupling the feed bar to a triggerof a surgical clip applier.

An exemplary method for advancing a surgical clip through an elongateshaft of a surgical clip applier is also provided. In one embodiment, afeed bar can be distally advanced within an elongate shaft of a surgicalclip applier to distally drive a feeder shoe disposed within theelongate shaft and thereby distally advance at least one clip. The feedbar can be distally advanced by, for example, actuating a triggercoupled to a housing that is mated to a proximal end of the elongateshaft. In one exemplary embodiment, when the feed bar is distallyadvanced, an advancer on the distal end of the feed bar can engage adistal-most clip and advance the clip between opposed jaws formed on adistal end of the elongate shaft. The method can also include proximallyretracting the feed bar within the elongate shaft while the feeder shoeis maintained in a substantially fixed position.

In another exemplary embodiment, a method for applying a surgical clipis provided and includes moving a trigger coupled to a housing a firstdistance toward a closed position to actuate a clip advancing assemblydisposed within the housing, thereby advancing a clip into a jawassembly formed on a distal end of the elongate shaft, and furthermoving the trigger a second distance toward the closed position toactuate a clip forming assembly disposed within the housing, therebyforming the clip disposed within the jaw assembly. The trigger ispreferably pliant relative to the clip advancing assembly duringactuation of the clip forming assembly. The clip forming assembly canalso be pliant relative to the jaw assembly during actuation thereof.

In other aspects, an overload mechanism is provided for use with asurgical device. In one exemplary embodiment, the overload mechanism caninclude a force-receiving member pivotally and slidably disposed in ahousing and having a surface with a first end and an opposed second end,and a biasing assembly disposed in the housing and adapted to resistmovement of the force-receiving member. In an exemplary embodiment, theresistance increases from the first end to the second end.

The force-receiving member can have a variety of configurations, but inone embodiment the force-receiving surface formed thereon is positionedwithin an opening in the housing. The force-receiving surface caninclude a first portion that is adapted to receive a force for pivotallymoving the force-receiving member within the housing, and a secondportion that is adapted to receive a force for slidably moving theforce-receiving member within the housing. The biasing assembly can alsohave a variety of configurations, but in one exemplary embodiment thebiasing assembly can include a spring disposed around a spring post, anda plunger slidably disposed relative to the spring post and having ahead formed thereon and adapted to compress the spring upon slidablemovement of the plunger toward the spring post.

In another embodiment, the housing can include a pivoting assembly thatis coupled between the force-receiving member and the biasing assemblysuch that pivoting assembly is adapted to transfer a force applied tothe force-receiving member to the biasing assembly to overcome theresistance. In one exemplary embodiment, the pivoting assembly caninclude a toggle link that is pivotally coupled to the force-receivingmember, and a pivot link that is pivotally coupled to the toggle linkand that is adapted to apply a force to the biasing assembly uponpivotal movement thereof.

In another embodiment, a surgical clip applier is provided having anoverload mechanism for preventing overload of a closing force applied tojaws of the clip applier. In one exemplary embodiment, the surgical clipapplier can include a housing having a trigger movably coupled thereto,an elongate shaft extending from the housing with opposed jaws formed ona distal end thereof and movable between an open position and a closedposition, and a camming assembly disposed within the housing and theelongate shaft and coupled to the trigger. The camming assembly can beadapted to apply a closing force to the jaws upon actuation of thetrigger to move the jaws from the open position toward the closedposition. The camming assembly can also be adapted to transfer theclosing force to an overload mechanism disposed within the housing whenthe closing force is greater than a resistance of the overload mechanismthat is applied to the camming assembly. In an exemplary embodiment, theresistance of the overload mechanism correlates to a force required tomove the jaws from the open position toward the closed position.

While various techniques can be used to couple the camming assembly tothe overload mechanism, in one exemplary embodiment the camming assemblymoves relative to a force-receiving surface of the overload mechanismsuch that the closing force of the camming assembly is applied acrossthe force-receiving surface of the overload mechanism as the trigger isactuated to cause the camming assembly to move the jaws from the openposition toward the closed position. The force-receiving surface of theoverload mechanism can be adapted to resist movement in a proximaldirection and the resistance can increase as the trigger is actuated tocause the camming assembly to move relative to the force-receivingsurface and to move the jaws from the open position toward the closedposition.

In another exemplary embodiment, the overload mechanism can include ahousing having a profile link slidably and pivotally disposed thereinand having the force-receiving surface formed thereon and positionedadjacent to an opening formed in the housing. The force-receivingsurface can include a first portion that is adapted to receive a forcefor pivotally moving the force-receiving member within the housing, anda second portion that is adapted to receive a force for slidably movingthe force-receiving member within the housing. The overload mechanismcan also include a biasing assembly that is adapted to apply aresistance to the profile link. In one exemplary embodiment, the biasingassembly can be coupled to the profile link by a pivoting assembly thatis adapted to pivot upon pivotal movement of the profile link, and thatis adapted to slide upon slidable movement of the profile link to applya force to the biasing assembly to overcome the resistance.

Methods for applying a surgical clip applier having an overloadmechanism are also provided. In one exemplary embodiment, a closingforce can be applied to a pair of opposed jaws formed on a surgical clipapplier. The closing force can be effective to move the opposed jawsfrom an open position to a closed position. When the closing force isgreater than a threshold force of an overload mechanism, the closingforce is transferred to the overload mechanism disposed within thesurgical clip applier. In an exemplary embodiment, the threshold forceof the overload mechanism increases as the jaws are moved from an openposition toward the closed position.

While the overload mechanism can have a variety of configurations, inone embodiment the overload mechanism can include a force-receivingelement that is adapted to receive the closing force, and a biasingassembly that is adapted to resist movement of the force-receivingelement in response to the closing force. The surgical clip applier caninclude a camming assembly that is adapted to apply the closing force tothe jaws, and that includes a roller member that rolls across theforce-receiving element as the closing force is applied to the jaws. Thethreshold force of the overload mechanism can increase as the rollermember rolls across the force-receiving element. In particular, when theroller member rolls across a first portion of the force-receivingelement, the force-receiving elements can pivot if the closing force isgreater than the threshold force, and when the roller member rollsacross a second portion of the force-receiving element, theforce-receiving element can slide if the closing force is greater thanthe threshold force. In an exemplary embodiment, the threshold forcerequired to pivot the force-receiving element is less than the thresholdforce required to slide the force-receiving element.

In other aspects, a surgical clip applier is provided and it can includea clip advancing assembly coupled to a trigger and adapted to advance atleast one surgical clip through an elongate shaft extending from ahousing, and a clip forming assembly coupled to a trigger and adapted toactuate a jaw assembly formed on a distal end of the elongate shaft toform a surgical clip. The trigger can be coupled to the housing andadapted to actuate the clip advancing assembly and the clip formingassembly. In an exemplary embodiment, the trigger has two sequentialstages of actuation. The trigger can be effective to actuate the clipadvancing assembly during the first stage of actuation, and it can beeffective to actuate the clip forming assembly during the second stageof actuation while being pliant relative to the clip advancing assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A is a side view of one exemplary embodiment of a surgical clipapplier;

FIG. 1B is an exploded view of the surgical clip applier shown in FIG.1A;

FIG. 2A is a top view of a jaw retainer assembly of the surgical clipapplier shown in FIG. 1A;

FIG. 2B is a bottom view of the jaw retainer assembly shown in FIG. 2A;

FIG. 2C is a side view of the jaw retainer assembly shown in FIG. 2B;

FIG. 2D is a cross-sectional view of the jaw retainer assembly shown inFIG. 2C taken across line D-D;

FIG. 3A is a top view of a feeder shoe for use with the jaw retainerassembly shown in FIGS. 2A-2D;

FIG. 3B is a bottom view of the feeder shoe shown in FIG. 3A;

FIG. 4A is a side perspective view of a feed bar that is configured toadvance the feeder shoe of FIGS. 3A and 3B through the jaw retainerassembly shown in FIGS. 2A-2D;

FIG. 4B is a side view of the proximal end of the feed bar shown in FIG.4A and the proximal end of the jaw retainer shaft shown in FIGS. 2A and2B, showing the feed bar in a proximal-most position;

FIG. 4C is a side view of the feed bar and jaw retainer shaft shown inFIG. 4B, showing the feed bar in a distal-most position;

FIG. 4D is a side view of another embodiment of a proximal end of a feedbar shown in connection with the proximal end of the jaw retainer shaftshown in FIGS. 2A and 2B, showing the feed bar in the proximal-mostposition;

FIG. 4E is a side view of the feed bar and jaw retainer shaft shown inFIG. 4D, showing the feed bar in a distal-most position;

FIG. 4F is a side view of yet another embodiment of a proximal end of afeed bar shown in connection with the proximal end of the jaw retainershaft shown in FIGS. 2A and 2B, showing the feed bar in theproximal-most position;

FIG. 4G is a side view of the feed bar and jaw retainer shaft shown inFIG. 4F, showing the feed bar in an intermediate position;

FIG. 4H is a side view of the feed bar and jaw retainer shaft shown inFIG. 4F, showing the feed bar in a distal-most position;

FIG. 5A is a side perspective view of an advancer that is configured tocouple to a distal end of the feed bar shown in FIG. 4A;

FIG. 5B is a side perspective view of another embodiment of an advancerthat is configured to couple to a distal end of the feed bar shown inFIG. 4A;

FIG. 6A is a cross-sectional view of a clip advancing assembly, whichincludes the jaw retainer assembly shown in FIGS. 2A-2D, the feeder shoeshown in FIGS. 3A-3B, and the feed bar shown in FIG. 4A, showing thefeed bar in an initial, proximal position relative to the clip track ofthe jaw retainer assembly;

FIG. 6B is a cross-sectional view of the clip advancing assembly shownin FIG. 6A, showing the feed bar moved in a distal direction;

FIG. 6C is a cross-sectional view of the clip advancing assembly shownin FIG. 6B, showing the feed bar moved further distally, thereby movingthe feeder shoe and a clip supply disposed distally of the feeder shoein a distal direction;

FIG. 6D is a cross-sectional view of the clip advancing assembly shownin FIG. 6C, showing the feed bar returned to the initial, proximalposition, shown in FIG. 6A, while the feeder shoe and clip supply remainin the advanced position shown in FIG. 6C;

FIG. 6E is a bottom perspective view of the advancer shown in FIG. 5Adisposed within the clip track of the jaw retainer assembly shown inFIGS. 2A-2D, showing the advancer in a proximal-most position;

FIG. 6F is a bottom perspective view of the advancer shown in FIG. 6E,showing the advancer in a distal-most position after advancing a clipinto the jaws of the surgical clip applier;

FIG. 7 is a side perspective view of a pair of jaws of the surgical clipapplier shown in FIG. 1A;

FIG. 8 is a side perspective view of a cam for use with the jaws shownin FIG. 7;

FIG. 9 is a top perspective view of a push rod that is adapted to coupleto the cam shown in FIG. 8 for moving the cam relative to the jaws shownin FIG. 7;

FIG. 10A is a top view of the cam shown in FIG. 8 coupled to the jawsshown in FIG. 7, showing the cam in an initial position and the jawsopen;

FIG. 10B is a top view of the cam shown in FIG. 8 coupled to the jawsshown in FIG. 7, showing the cam advanced over the jaws and the jaws ina closed position;

FIG. 11 is a top perspective view of a tissue stop that is adapted tocouple to a distal end of the clip track of the jaw retainer assemblyshown in FIGS. 2A-2D;

FIG. 12 is a top view of a distal end of the surgical clip applier shownin FIG. 1A showing the tissue stop shown in FIG. 1 positioned betweenthe jaws shown in FIG. 7;

FIG. 13 is a side, partially cross-sectional view of the handle portionof the surgical clip applier shown in FIG. 1A;

FIG. 14 is a side perspective view of a trigger insert of the surgicalclip applier shown in FIG. 1A;

FIG. 15A is a side perspective view of one half of a feed bar coupler ofthe surgical clip applier shown in FIG. 1A;

FIG. 15B is a side perspective view of the other half of the feed barcoupler shown in FIG. 15A;

FIG. 16 is a top perspective view of a flexible link that forms part ofa clip advancing assembly of the surgical clip applier shown in FIG. 1A;

FIG. 17A is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 1A, showing a clipadvancing assembly in an initial position;

FIG. 17B is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 17A, showing the clipadvancing assembly partially actuated;

FIG. 17C is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 17B, showing the clipadvancing assembly fully actuated;

FIG. 17D is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 17A, showing a clipforming assembly actuated;

FIG. 18 is a side view of a closure link roller that forms part of aclip forming assembly of the surgical clip applier shown in FIG. 1A;

FIG. 19 is a top perspective view of a closure link that couples to theclosure link roller shown in FIG. 18 to form part of a clip formingassembly of the surgical clip applier shown in FIG. 1A;

FIG. 20A is a top perspective view of a closure link coupler thatcouples to the closure link shown in FIG. 19 and that also forms part ofthe clip forming assembly of the surgical clip applier shown in FIG. 1A;

FIG. 20B is a bottom view of the closure link shown in FIG. 20A coupledto the push rod of FIG. 9 and having one embodiment of a biasing elementdisposed therein;

FIG. 20C is a bottom view of the closure link shown in FIG. 20A coupledto the push rod of FIG. 9 and having another embodiment of a biasingelement disposed therein;

FIG. 21A is an enlarged side perspective view of an anti-backupmechanism of the surgical clip applier shown in FIG. 1A;

FIG. 21B is a perspective view of a pawl mechanism of the anti-backupmechanism shown in FIG. 21A;

FIG. 22A is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 1A, showing theanti-backup mechanism in an initial position;

FIG. 22B is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 22A, showing theanti-backup mechanism in a partially actuated position;

FIG. 22C is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 22B, showing theanti-backup mechanism in a fully actuated position;

FIG. 22D is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 22C, showing theanti-backup mechanism returning to an initial position;

FIG. 22E is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 22D, showing theanti-backup mechanism returned to the initial position;

FIG. 23A is an exploded view of an overload mechanism of the surgicalclip applier shown in FIG. 1A;

FIG. 23B is a partially cross-sectional view of the overload mechanismshown in FIG. 23A, showing the closure link roller first coming intocontact with the profile link;

FIG. 23C is a partially cross-sectional view of the overload mechanismshown in FIG. 23B, showing the closure link roller applying a force tothe profile link causing the profile link to pivot;

FIG. 23D is a perspective view of another embodiment of an overloadmechanism for use with a surgical clip applier;

FIG. 24A is a side perspective view of a clip quantity indicator wheelof the surgical clip applier shown in FIG. 1A;

FIG. 24B is a side view of a clip quantity indicator wheel shown in FIG.24A;

FIG. 25 is a top perspective view of a clip quantity actuator for usewith the clip quantity indicator wheel shown in FIG. 24;

FIG. 26A is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 1A, showing movementof the clip quantity actuator of FIG. 25 and the clip quantity indicatorwheel of FIG. 24; and

FIG. 26B is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 26A, showing furthermovement of the clip quantity actuator of FIG. 25 and the clip quantityindicator wheel of FIG. 24.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally provides a surgical clip applier andmethods for using a surgical clip applier to apply surgical clips to avessel, duct, shunt, etc., during a surgical procedure. An exemplarysurgical clip applier can include a variety of features to facilitateapplication of a surgical clip, as described herein and illustrated inthe drawings. However, a person skilled in the art will appreciate thatthe surgical clip applier can include only some of these features and/orit can include a variety of other features known in the art. Thesurgical clip applier described herein is merely intended to representcertain exemplary embodiments.

FIG. 1A illustrates one exemplary surgical clip applier 10. As shown,the clip applier 10 generally includes a housing 12 having a stationaryhandle 14 and a movable handle or trigger 16 that is pivotally coupledto the housing 12. An elongate shaft 18 extends from the housing 12 andit includes a pair of opposed jaws 20 formed on a distal end thereof forcrimping a surgical clip. The elongate shaft 18 can be rotatably coupledto the housing 12, and it can include a rotation knob 22 for rotatingthe shaft 18 relative to the housing 12. FIG. 1B illustrates an explodedview of the surgical clip applier 10 shown in FIG. 1A, and the variouscomponents will be described in more detail below.

FIGS. 2A-12 illustrate exemplary embodiments of the various componentsof the shaft 18 of the surgical clip applier 10. In general, referringto FIG. 1B, the shaft 18 includes an outer tube 24 that houses the shaftcomponents, which can include a jaw retaining assembly 26 having a jawretainer shaft 28 with a clip track 30 and a push rod channel 32 formedthereon. The jaws 20 can be configured to mate to a distal end of theclip track 30. The shaft assembly 18 can also include a clip advancingassembly, which in one exemplary embodiment can include a feeder shoe 34that is adapted to be slidably disposed within the clip track 30 toadvance a series of clips 36 positioned therein, and a feed bar 38 thatis adapted to drive the feeder shoe 34 through the clip track 30. Thefeed bar 38 can include an advancer assembly 40 that is adapted to mateto a distal end thereof for advancing a distal-most clip into the jaws20. The shaft assembly 18 can also include a clip forming or cammingassembly, which in one exemplary embodiment can include a cam 42 that isadapted to slidably mate to the jaws 20, and a push rod 44 that cancouple to the cam 42 to move the cam 42 relative to the jaws 20. Theshaft assembly can also include a tissue stop 46 that can mate to adistal end of the clip track 30 for facilitating positioning of the jaws20 relative to a surgical site.

The various components of one exemplary clip advancing assembly areshown in more detail in FIGS. 2A-5. Referring first to FIGS. 2A-2D, thejaw retaining assembly 26 is shown and it includes an elongate,substantially planar jaw retainer shaft 28 having a proximal end 28 athat mates to the outer tube 24, and a distal end 28 b that is adaptedto mate to the jaws 20. While a variety of techniques can be used tomate the proximal end 28 a of the jaw retainer shaft 28 to the outertube 24, in the illustrated embodiment the proximal end 28 a includesteeth 31 formed on opposed sides thereof that are adapted to be receivedwithin corresponding holes or openings (not shown) formed in the outertube 24, and a cut-out 29 formed therein that allows the opposed sidesof the proximal end 28 a to deflect or to form a spring. In particular,the cut-out 29 allows the opposed sides of the proximal end 28 a of thejaw retainer shaft 28 to be compressed toward one another when the jawretainer shaft 28 is inserted in the outer tube 24. Once the teeth 31are aligned with the corresponding openings in the outer tube 24, theproximal end 28 a of the jaw retainer shaft 28 will return to itsoriginal, uncompressed configuration thereby causing the teeth 31 toextend into the corresponding openings to engage the outer 24. As willbe discussed in more detail below with respect to FIG. 4A, the devicecan also include a feature to prevent compression of the opposed sidesof the proximal end 28 a of the jaw retainer shaft 28 during use of thedevice to prevent accidental disengagement of the teeth 31 from theouter tube 24.

A variety of techniques can also be used to mate the distal end 28 b ofthe jaw retainer shaft 28 to the jaws 20, however in the illustratedembodiment the distal end 28 b of the jaw retainer shaft 28 includesseveral cut-outs or teeth 78 formed therein for mating withcorresponding protrusions or teeth 94 formed on the jaws 20, which willbe discussed in more detail below with respect to FIG. 7. The teeth 78allow a proximal portion of the jaws 20 to be substantially co-planarwith the jaw retainer shaft 28.

The jaw retaining assembly 26 can also include a push rod channel 32formed thereon for slidably receiving the push rod 44, which is used toadvanced the cam 42 over the jaws 20, as will be discussed in moredetail below. The push rod channel 32 can be formed using a variety oftechniques, and it can have any shape and size depending on the shapeand size of the push rod 44. As shown in FIG. 2D, the push rod channel32 is fixedly attached, e.g., by welding, to a superior surface of theretainer shaft 28, and it has a substantially rectangular shape anddefines a pathway 32 a extending therethrough. The push rod channel 32can also extend along all or only a portion of the retainer shaft 28. Aperson skilled in the art will appreciate that the jaw retainingassembly 26 does not need to include a push rod channel 32 forfacilitating movement of the push rod 44 within the elongate shaft 18 ofthe surgical clip applier 10.

As is further shown in FIGS. 2A-2D, the jaw retaining assembly 26 canalso include a clip track 30 mated thereto or formed thereon. The cliptrack 30 is shown mated to an inferior surface of the jaw retainer shaft28, and it extends distally beyond the distal end 28 b of the jawretainer shaft 28 to allow a distal end 30 b of the clip track 30 to besubstantially aligned with the jaws 20. In use, the clip track 30 isconfigured to seat at least one, and preferably a series, of clipstherein. Accordingly, the clip track 30 can include opposed side rails80 a, 80 b that are adapted to seat opposed legs of one or more clipstherein, such that the legs of the clips are axially aligned with oneanother. In an exemplary embodiment, the clip track 30 can be configuredto seat about twenty clips that are pre-disposed within the clip track30 during manufacturing. A person skilled in the art will appreciatethat the shape, size, and configuration of the clip track 30 can varydepending on the shape, size, and configuration of clips, or otherclosure devices such as staples, adapted to be received therein.Moreover, a variety of other techniques can be used, instead of a cliptrack 30, to retain a clip supply with the elongate shaft 18.

The clip track 30 can also include several openings 30 c formed thereinfor receiving a tang 82 a formed on a feeder shoe 34 adapted to bedisposed within the clip track 30, as will be discussed in more detailbelow. In an exemplary embodiment, the clip track 30 includes a quantityof openings 30 c that corresponds to at least the number of clipsadapted to be pre-disposed within the device 10 and applied during use.The openings 30 c are preferably equidistant from one another to ensurethat the tang 82 a on the feeder shoe 34 engages an opening 30 c eachtime the feeder shoe 34 is advanced. While not shown, the clip track 30can include detents, rather than openings 30 c, or it can include otherfeatures that allow the clip track 30 to engage the feeder shoe 34 andprevent distal movement, yet allow proximal movement, of the feeder shoe34. The clip track 30 can also include a stop tang 118 formed thereon,as shown in FIG. 2B, that is effective to be engaged by a correspondingstop tang formed on the feeder shoe 34 to prevent movement of the feedershoe 34 beyond a distal-most position, as will be discussed below. Thestop tang 118 can have a variety of configurations, but in one exemplaryembodiment it is in the form of two adjacent tabs that extend toward oneanother to enclose a portion of the clip track, thus allowing clips topass therethrough.

An exemplary feeder shoe 34 is shown in more detail in FIGS. 3A and 3B,and it can be adapted to directly driving clips through the clip track30. While the feeder shoe 34 can have a variety of configurations, and avariety of other techniques can be used to drive clips through the cliptrack 30, in an exemplary embodiment the feeder shoe 34 has a generallyelongate shape with proximal and distal ends 34 a, 34 b. The distal end34 b can be adapted to cradle the proximal-most clip in the clip track30 to push the clip(s) through the clip track 30. In the illustratedexemplary embodiment, the distal end 34 b is substantially v-shaped forseating a v-shaped bight portion of a clip. The distal end 34 b alsoincludes a rectangular-shaped notch 34 c formed therein for allowing theadvancer 40 to engage a distal-most clip and advance it into the jaws20, as will be discussed in more detail below. The distal end 34 b can,of course, vary depending on the configuration of the clip, or otherclosure mechanism, being used with the device 10.

In another exemplary embodiment, the feeder shoe 34 can also includefeatures to facilitate distal movement of the feeder shoe 34 within theclip track 30, and to substantially prevent proximal movement of thefeeder shoe 34 within the clip track 30. Such a configuration willensure advancement and proper positioning of the clips within the cliptrack 30, thus allowing a distal-most clip to be advanced between thejaws 20 with each actuation of the trigger 16, as will be discussed inmore detail below. In the illustrated exemplary embodiment, the feedershoe 34 includes a tang 82 a formed on a superior surface 34 s thereofand angled proximally for engaging one of the openings 30 c formed inthe clip track 30. In use, the angle of the tang 82 a allows the feedershoe 34 to slide distally within the clip track 30. Each time the feedershoe 34 is advanced, the tang 82 a will move in a distal direction fromone opening 30 c to the next opening 30 c in the clip track 30. Theengagement of the tang 82 a with the opening 30 c in the clip track 30will prevent the feeder shoe 34 from moving proximally to return to theprevious position, as will be described in more detail below.

In order to facilitate proximal movement of the feeder shoe 34 withinthe clip track 30, the feeder shoe 34 can also include a tang 82 bformed on the inferior surface 34 i thereof, as shown in FIG. 3B, forallowing the feeder shoe 34 to be engaged by the feed bar 38 (FIG. 4A)as the feed bar 38 is moved distally. The inferior tang 82 b is similarto the superior tang 82 a in that it can be angled proximally. In use,each time the feed bar 38 is moved distally, a detent 84 formed in thefeed bar 38 can engage the inferior tang 82 b and move the feeder shoe34 distally a predetermined distance within the clip track 30. The feedbar 38 can then be moved proximally to return to its initial position,and the angle of the inferior tang 82 b will allow the tang 82 b toslide into the next detent 84 formed in the feed bar 38. As previouslynoted, a variety of other features rather than tangs 82 a, 82 b andopenings 30 c or detents 84 can be used to control movement of thefeeder shoe 34 within the clip track 30.

As previously mentioned, the feeder shoe 34 can also include a stopformed thereon that is adapted to stop movement of the feeder shoe 34when the feeder shoe 34 is in the distal-most position and there are noclips remaining in the device 10. While the stop can have a variety ofconfigurations, FIGS. 3A and 3B illustrate a third tang 82 c formed onthe feeder shoe 34 and extending in an inferior direction for engagingthe stop tang 118 (FIG. 2B) formed on the clip track 30. The third tang82 c is positioned such that it will engage the stop tang 118 on theclip track 30 when the feeder shoe 34 is in a distal-most position,thereby preventing movement of the feeder shoe 34 and the feed bar 38when the clip supply is depleted.

FIG. 4A illustrates an exemplary feed bar 38 for driving the feeder shoe34 through the clip track 30 of the jaw retaining assembly 26. As shown,the feed bar 38 has a generally elongate shape with proximal and distalends 38 a, 38 b. The proximal end 38 a of the feed bar 38 a can beadapted to mate to a feed bar coupler 50 (FIG. 1B), which will bediscussed in more detail below. The feed bar coupler 50 can mate to afeed link 52 that is effective, upon actuation of the trigger 16, toslidably move the feed bar 38 in a distal direction within the elongateshaft 18. The distal end 38 b of the feed bar 38 b can be adapted tomate to an advancer 40, 40′, exemplary embodiments of which are shown inFIGS. 5A and 5B, that is effective to drive a distal-most clip disposedwithin the clip track 30 into the jaws 20, which will be discussed inmore detail below.

As previously mentioned, the proximal end 38 a of the feed bar 38 caninclude a feature to prevent compression of the opposed sides of theproximal end 28 a of the jaw retainer shaft 28 (FIGS. 2A and 2B) duringuse of the device to prevent accidental disengagement of the teeth 31from the outer tube 24. In one exemplary embodiment, shown FIGS. 4A-4C,the proximal end 38 a of the feed bar 38 can include a protrusion 39formed thereon that is adapted to extend into the opening 29 formed inthe proximal end 28 a of the jaw retainer shaft 28. When the feed bar 38is in a proximal-most position (i.e., when the trigger 16 is in an openposition), the protrusion 39 will be positioned at the proximal end ofthe opening 29, as shown in FIG. 4B, allowing the proximal end 28 a ofthe jaw retainer shaft 28 to compress to allow the shaft 28 to slideinto the outer tube 24. When the feed bar 38 is in a distal-mostposition (i.e., when the trigger 16 is in at least a partially closedposition), the protrusion 39 will be positioned at an intermediatelocation adjacent to the teeth 31 as shown in FIG. 4C, to preventcompression of the proximal end 28 a of the jaw retainer shaft 28. Thisis particularly advantageous during use of the device, as the protrusion39 will prevent accidental disengagement of the jaw retainer shaft 28from the outer tube 24 during use of the device. While FIGS. 4A-4Cillustrate a protrusion 39 having a rectangular cross-sectional shapewith rounded edges, the protrusion 39 can have a variety of other shapesand sizes. For example, as shown in FIGS. 4D and 4E, the protrusion 39′has a cross-sectional shape that is somewhat triangular with a taperingend that is adapted to extend between the teeth 31 to further ensurethat the proximal end 28 a of the jaw retainer shaft 28 can not becompressed during use of the device. More than one protrusion can alsobe used. For example, FIGS. 4F-4H illustrate another embodiment in whichthe proximal end 38 a′ of the feed bar 38 includes two protrusions 39 a,39 b formed thereon and spaced a distance apart from one another. Thetwo protrusions 39 a, 39 b will prevent compression of the proximal end28 a of the jaw retainer shaft 28 when the feed bar 38 is in aproximal-most position, as shown in FIG. 4F, and when the feed bar 38 isin a distal-most position, as shown in FIG. 4H. Compression of theproximal end 28 a of the jaw retainer shaft 28 can only occur when thefeed bar 38 is at an intermediate position such that the teeth 31 arepositioned between the protrusions 39 a, 39 b, as shown in FIG. 4G.

As was also previously mentioned, the feed bar 38 can include one ormore detents 84 formed therein for engaging the inferior tang 82 bformed on the feeder shoe 34. The quantity of detents 84 can vary, butin an exemplary embodiment the feed bar 38 has a quantity of detents 84that corresponds to or is greater than a quantity of clips adapted to bedelivered by the device 10, and more preferably it has one more detent84 than the quantity of clips adapted to be delivered by the device 10.By way of non-limiting example, the feed bar 38 can include eighteendetents 84 formed therein for delivering seventeen clips that arepre-disposed within the clip track 30. Such a configuration allows thefeed bar 38 to advance the feeder shoe 34 seventeen times, therebyadvancing seventeen clips into the jaws 20 for application. The detents84 are also preferably equidistant from one another to ensure that thefeeder shoe 34 is engaged and advanced by the feed bar 38 each time thefeed bar 38 is advanced.

The feed bar 38 can also include a feature to control the amount ofmovement of the feed bar 38 relative to the clip track 30. Such aconfiguration will ensure that the feeder shoe 34 is advanced apredetermined distance each time the trigger 16 is actuated, therebyadvancing only a single clip into the jaws 20. While a variety oftechniques can be used to control the distal of movement of the feed bar38, in an exemplary embodiment the feed bar 38 can include a protrusion86 formed thereon that is adapted to be slidably received within acorresponding slot 88 (FIG. 2B) formed in the jaw retainer shaft 28. Thelength of the slot 88 is effective to limit movement of the protrusion86 therein, thus limiting movement of the feed bar 38. Accordingly, inuse the feed bar 38 can slide between a fixed proximal position and afixed distal position with respect to the clip track 30, therebyallowing the feed bar 38 to advance the feeder shoe 34 by apredetermined distance with each advancement of the feed bar 38.

FIG. 5A illustrates one exemplary embodiment of an advancer 40 that isadapted to mate to the distal end 38 b of the feed bar 38 and which iseffective to drive a distal-most clip from the clip track 30 into thejaws 20. A variety of techniques can be used to mate the advancer 40 tothe feed bar 38, but in the illustrated embodiment the proximal end 40 aof the advancer 40 is in the form of a female connector that is adaptedto receive the male connector formed on the distal end 38 b of the feedbar 38. The advancer 40 preferably fixedly mates to the feed bar 38,however it can optionally be integrally formed with the feed bar 38. Thedistal end 40 b of the feed bar 38 is preferably adapted to advance aclip into the jaws 20 and thus the distal end 40 b of the advancer 40can include, for example, a clip-pusher member 90 formed thereon. Theclip-pusher member 90 can have a variety of shapes and sizes, but in oneexemplary embodiment it has an elongate shape with a recess 92 formed inthe distal end thereof for seating the bight portion of a clip. Theshape of the recess 92 can vary depending on the particularconfiguration of the clip. The clip-pusher member 90 can also extend atan angle in a superior direction with respect to a longitudinal axis Aof the advancer 40. Such a configuration allows the clip-pusher member90 to extend into the clip track 30 to engage a clip, while theremainder of the advancer 40 extends substantially parallel to the cliptrack 30. FIG. 5B illustrates another exemplary embodiment of aclip-pusher member 90′ of an advancer 40′. In this embodiment, theclip-pusher member 90′ is slightly more narrow and it has a small recess92′ formed in the distal-most end thereof. In use, the advancer 40 canengage and advance only the distal-most clip disposed within the cliptrack 30 into the jaws 20. This is due to the positioning of the feedbar 38, which is slidably movable between a fixed proximal and distalpositions, as previously discussed.

FIGS. 6A-6G illustrate the clip advancing assembly in use, and inparticular FIGS. 6A-6D illustrate movement of the feed bar 38 within theclip track 30 to advance the feeder shoe 34 and clip supply 36, andFIGS. 6E-6F illustrate movement of the advancer 40 to advance adistal-most clip into the jaws 20. The components in the housing 12 thatare used to actuate the clip advancing assembly will be discussed inmore detail below.

As shown in FIG. 6A, in the resting position the feed bar 38 is in aproximal-most position such that the protrusion 86 is positionedproximally within the elongate slot 88 in the jaw retainer shaft 28. Thefeeder shoe 34 is disposed within the clip track 30 and, assuming thedevice 10 has not yet been used, the feeder shoe 34 is in aproximal-most position such that the superior tang 82 a on the feedershoe 34 is engaged with the proximal-most or first opening 30 c ₁ formedin the clip track 30 to prevent proximal movement of the feeder shoe 34,and the inferior tang 82 b on the feeder shoe 34 is positioned betweenthe first detent 84 ₁ and the second detent 84 ₂ in the feed bar 38,such that the inferior tang 82 b is biased in a superior direction bythe feed bar 38. The detents 84 in the feed bar are labeled sequentiallyas 84 ₁, 84 ₂, etc., and the openings 30 c in the clip track 30 arelabeled sequentially as 30 c ₁, 30 c ₂, etc. As is further shown in FIG.6A, a series of clips 36, labeled sequentially as 36 ₁, 36 ₂, . . . 36_(x) with 36 _(x) being the distal-most clip, are positioned within theclip track 30 distal of the feeder shoe 34.

Upon actuation of the trigger 16, the feed bar 38 is advanced distally,causing the protrusion 86 to slide distally within the slot 88. As thefeed bar 38 moves distally, the inferior tang 82 b on the feeder shoe 34will slide into the first detent 84 ₁ in the feed bar 38. Further distalmovement of the feed bar 38 will cause the first detent 84 ₁ to engagethe inferior tang 82 b, as shown in FIG. 6B, and to move the feeder shoe34 and clip supply 36 ₁, 36 ₂, etc. in a distal direction. As shown inFIG. 6C, when the protrusion 86 abuts the distal end of the elongateslot 88 in the jaw retainer shaft 28, the feed bar 38 is prevented fromfurther distal movement. In this position, the feeder shoe 34 hasadvanced a predetermined distance to advance the clip supply 36 ₁, 36 ₂,. . . 36 _(x) within the clip track 30 by a predetermined distance. Thesuperior tang 82 a of the feeder shoe 34 has been advanced into thesecond opening 30 c ₂ in the clip track 30 to prevent proximal movementof the feeder shoe 34, and the inferior tang 82 b on the feeder shoe 34is still engaged by the first detent 84 ₁ in the feed bar 38.

Movement of the feed bar 38 from the initial, proximal-most position,shown in FIG. 6A, to the final, distal-most position, shown in FIG. 6C,will also advance the distal-most clip 36 _(x) into the jaws 20. Inparticular, as shown in FIG. 6E, distal movement of the feed bar 38 willcause the clip-pusher member 90 of the advancer 40, which is attached tothe distal end of the feed bar 38, to engage the distal-most clip 36_(x) disposed within the clip track 30 and to advance the clip 36 _(x)into the jaws 20, as shown in FIG. 6F. In an exemplary embodiment, theadvancer 40 will engage and initiate advancement of the distal-most clip36 _(x) prior to engaging and initiating advancement of the feeder shoe34. As a result the distal-most clip 36 _(x) will advance a distancethat is greater than a distance traveled by the feeder shoe 34. Such aconfiguration allows only the distal-most clip 36 _(x) to be advancedinto the jaws 20 without accidentally advancing an additional clip intothe jaws 20.

Once the clip 36 _(x) has been partially or fully formed, the trigger 16can be released to release the formed clip 36 _(x). Release of thetrigger 16 will also retract the feed bar 38 in a proximal directionuntil the protrusion 86 returns to the initial proximal-most positionwithin the elongate slot 88, as shown in FIG. 6D. As the feed bar 38 isretracted proximally, the feeder shoe 34 will not move proximally sincethe superior tang 82 a will engage the second opening 30 c ₂ in the cliptrack 30. The inferior tang 82 b will not interfere with proximalmovement of the feed bar 38, and once the feed bar 38 is in the initial,proximal-most position, as shown, the inferior tang 82 b will bepositioned between the second detent 84 ₂ and the third detent 84 ₃ inthe feed bar 38.

The process can be repeated to advance another clip into the jaws 20.With each actuation of the trigger 16, the inferior tang 82 b will beengaged by the next detent, i.e., detent 84 ₂ formed in the feed bar 38,the superior tang 82 a on the feeder shoe 34 will be moved distally intothe next opening, i.e., opening 30 c ₃ on the clip track 30, and thedistal-most clip will be advanced into the jaws 20 and released. Wherethe device 10 includes a predetermined amount of clips, e.g., seventeenclips, the trigger 16 can be actuated seventeen times. Once the lastclip has been applied, the stop, e.g., the third tang 82 c, on thefeeder shoe 34 can engage the stop tang 118 on the clip track 30 toprevent further distal movement of the feeder shoe 34.

FIGS. 7-9 illustrate various exemplary components of a clip formingassembly. Referring first to FIG. 7, an exemplary embodiment of the jaws20 are shown. As previously mentioned, the jaws 20 can include aproximal portion 20 a having teeth 94 for mating with correspondingteeth 78 formed on the jaw retaining shaft 28. Other techniques can,however, be used to mate the jaws 20 to the jaw retaining shaft 28. Forexample, a dovetail connection, a male-female connection, etc., can beused. Alternatively, the jaws 20 can be integrally formed with theretaining shaft 28. The distal portion 20 b of the jaws 20 can beadapted to receive a clip therebetween, and thus the distal portion 20 bcan include first and second opposed jaw members 96 a, 96 b that aremovable relative to one another. In an exemplary embodiment, the jawmembers 96 a, 96 b are biased to an open position, and a force isrequired to move the jaw members 96 a, 96 b toward one another. The jawmembers 96 a, 96 b can each include a groove (only one groove 97 isshown) formed therein on opposed inner surfaces thereof for receivingthe legs of a clip in alignment with the jaw members 96 a, 96 b. Thejaws members 96 a, 96 b can also each include a cam track 98 a, 98 bformed therein for allowing the cam 42 to engage the jaw members 96 a,96 b and move the jaw members 96 a, 96 b toward one another. In anexemplary embodiment, the cam track 98 a, 98 b is formed on a superiorsurface of the jaw members 96 a, 96 b.

FIG. 8 illustrates an exemplary cam 42 for slidably mating to andengaging the jaw members 96, 96 b. The cam 42 can have a variety ofconfigurations, but in the illustrated embodiment it includes a proximalend 42 a that is adapted to mate to a push rod 44, discussed in moredetail below, and a distal end 42 b that is adapted to engage the jawmembers 96 a, 96 b. A variety of techniques can be used to mate the cam42 to the push rod 44, but in the illustrated exemplary embodiment thecam 42 includes a female or keyed cut-out 100 formed therein and adaptedto receive a male or key member 102 formed on the distal end 44 b of thepush rod 44. The male member 102 is shown in more detail in FIG. 9,which illustrates the push rod 44. As shown, the male member 102 has ashape that corresponds to the shape of the cut-out 100 to allow the twomembers 42, 44 to mate. A person skilled in the art will appreciate thatthe cam 42 and the push rod 44 can optionally be integrally formed withone another. The proximal end 44 a of the push rod 44 can be adapted tomate to a closure link assembly, discussed in more detail below, formoving the push rod 44 and the cam 42 relative to the jaws 20.

As is further shown in FIG. 8, the cam 42 can also include a protrusion42 c formed thereon that is adapted to be slidably received within anelongate slot 20 c formed in the jaws 20. In use, the protrusion 42 cand the slot 20 c can function to form a proximal stop for the clipforming assembly.

Referring back to FIG. 8, the distal end 42 b of the cam 42 can beadapted to engage the jaw members 96 a, 96 b. While a variety oftechniques can be used, in the illustrated exemplary embodiment thedistal end 42 b includes a camming channel or tapering recess 104 formedtherein for slidably receiving the cam tracks 98 a, 98 b on the jawmembers 96 a, 96 b. In use, as shown in FIGS. 10A and 10B, the cam 42can be advanced from a proximal position, in which the jaw members 96 a,96 b are spaced a distance apart from one another, to a distal position,in which the jaw members 96 a, 96 b are positioned adjacent to oneanother and in a closed position. As the cam 42 is advanced over the jawmembers 96 a, 96 b, the tapering recess 104 will push the jaw members 96a, 96 b toward one another, thereby crimping a clip disposedtherebetween.

As previously mentioned, the surgical clip applier 10 can also include atissue stop 46 for facilitating positioning of the tissue at thesurgical site within jaws 20. FIG. 11 shows one exemplary embodiment ofa tissue stop 46 having proximal end and distal ends 46 a, 46 b. Theproximal end 46 a can be adapted to mate to a distal end of the cliptrack 30 for positioning the tissue stop 46 adjacent to the jaws 20.However, the tissue stop 46 can be integrally formed with the clip track30, or it can be adapted to mate to or be integrally formed with avariety of other components of the shaft 18. The distal end 46 b of thetissue stop 46 can have a shape that is adapted to seat a vessel, duct,shunt, etc. therebetween to position and aligned the jaws 20 relative tothe target site. As shown in FIG. 11 the distal end 46 b of the tissuestop 46 is substantially v-shaped. The distal end 46 b can also have acurved configuration to facilitate placement of the device through atrocar or other access tube. The distal end 46 b of the tissue stop 46can also optionally include other features to facilitate movement of theclip there over. For example, as shown in FIG. 11, the tissue stop 46includes a ramp 47 formed at a mid-portion of the distal end 46 b formaintaining a clip in alignment with the tip of the advancer assembly40. In particular, the ramp 47 can allow the apex of a clip to ridetherealong thus preventing the clip from becoming misaligned relative tothe advancer assembly 40 that is pushing the clip in a distal direction.A person skilled in the art will appreciate that the tissue stop 46 canhave a variety of other configurations, and it can include a variety ofother features to facilitate advancement of a clip therealong.

FIG. 12 illustrates the tissue stop 46 in use. As shown, the tissue stop46 is positioned just inferior to the jaws 20 and at a location thatallows a vessel, duct, shunt etc. to be received between the jaws 20. Asis further shown, a surgical clip 36 is positioned between the jaws 20such that the bight portion 36 a of the clip 36 is aligned with thetissue stop 46. This will allow the legs 36 b of the clip 36 to be fullypositioned around the vessel, duct, shunt, or other target site.

FIGS. 13-26B illustrate various exemplary internal components of thehousing 12 for controlling clip advancement and forming. As previouslydiscussed, the surgical clip applier 10 can include some or all of thefeatures disclosed herein, and it can include a variety of otherfeatures known in the art. In certain exemplary embodiments, theinternal components of the clip applier 10 can include a clip advancingassembly, that couples to the clip advancing assembly of the shaft 18,for advancing at least one clip through the elongate shaft 18 toposition the clip between the jaws 20, and a clip forming assembly, thatcouples to the clip forming assembly of the shaft 18, for closing thejaws 20 to form a partially or fully closed clip. Other exemplaryfeatures include an anti-backup mechanism for controlling movement ofthe trigger 16, an overload mechanism for preventing overload of theforce applied to the jaws 20 by the clip forming assembly, and a clipquantity indicator for indicating a quantity of clips remaining in thedevice 10.

FIGS. 13-16D illustrate an exemplary embodiment of a clip advancingassembly of the housing 12 for effecting movement of the feed bar 38within the shaft 18. In general, the clip advancing assembly can includea trigger insert 48 that is coupled to the trigger 16, a feed barcoupler 50 that can mate to a proximal end 38 a of the feed bar 38, anda feed link 52 that is adapted to extend between the trigger insert 48and the feed bar coupler 50 for transferring motion from the triggerinsert 48 to the feed bar coupler 50.

FIG. 14 illustrates the trigger insert 48 in more detail. The shape ofthe trigger insert 48 can vary depending on the other components of thehousing 12, but in the illustrated embodiment the trigger insert 48includes a central portion 48 a that is adapted to pivotally mate to thehousing 12, and an elongate portion 48 b that is adapted to extend intoand mate to the trigger 16. The central portion 48 a can include a bore106 extending therethrough for receiving a shaft for pivotally matingthe trigger insert 48 to the housing 12. The central portion 48 a canalso include a first recess 108 formed in a superior side edge forreceiving a portion of the feed link 52. The first recess 108 preferablyhas a size and shape that allows a portion of the feed link 52 to extendtherein such that the feed link 52 will be forced to pivot when thetrigger insert 48 pivots due to movement of the trigger 16. As shown inFIG. 14, the first recess 108 is substantially elongate and includes asubstantially circular portion formed therein for seating a shaft formedon a proximal end of the feed link 52, as will be discussed in moredetail with respect to FIG. 16. The trigger insert 48 can also include asecond recess 110 formed in a back side edge for receiving a closurelink roller 54 that is coupled to the push bar 44 for moving the cam 42to close the jaws 20, and ratchet teeth 112 formed on the bottom sideedge thereof for mating with a pawl 60 for controlling movement of thetrigger 16, as will be discussed in more detail below.

The exemplary feed bar coupler 50 is shown in more detail in FIGS. 15Aand 15B, and it can be adapted to couple the proximal end of the feedbar 38 to the distal end of the feed link 52. While a variety oftechniques can be used to mate the feed bar coupler 50 to the proximalend 38 a of the feed bar 38, in an exemplary embodiment the feed barcoupler 50 is formed from two separate halves 50 a, 50 b that matetogether to maintain the proximal end 38 a of the feed bar 38therebetween. When mated, the two halves 50 a, 50 b together define acentral shaft 50 c having substantially circular flanges 50 d, 50 eformed on opposed ends thereof and defining a recess 50 f therebetweenfor seating a distal portion of the feed link 52. The central shaft 50 cdefines a lumen 50 g therethrough for receiving the proximal end 38 a ofthe feed bar 38 and for locking the feed bar 38 in a substantially fixedposition relative to the feed bar coupler 50. The feed bar coupler 50can, however, be integrally formed with the feed bar 38, and it can havea variety of other shapes and sizes to facilitate mating with the feedlink 52.

FIG. 16 illustrates an exemplary feed link 52, which can extend betweenthe trigger insert 48 and the feed bar coupler 52. In general, the feedlink 52 can have a substantially planar elongate shape with proximal anddistal ends 52 a, 52 b. The proximal end 52 a is adapted to rotatablysit within the first recess 108 of the trigger insert 48 and thus, aspreviously discussed, it can include a shaft 53 (FIG. 1B) extendingtherethrough. The shaft 53 can be adapted to pivotally rotate within thefirst recess 108 of the trigger insert 48, thereby allowing the triggerinsert 48 to pivot the feed link 52. The distal end 52 b of the feedlink 52 can be adapted to couple to feed bar coupler 50 and thus, in anexemplary embodiment, it includes opposed arms 114 a, 114 b formedthereon and defining an opening 116 therebetween for seating the centralshaft 50 a of the feed bar coupler 50. The arms 114 a, 114 b areeffective to engage and move the coupler 50 as the feed link 52 pivotsabout a pivot axis X. The pivot axis X can be defined by the location atwhich the feed link 52 couples to the housing 12, and it can bepositioned anywhere on the feed link 52, but in the illustratedembodiment it is positioned adjacent to the proximal end 52 a of thefeed link 52.

In an exemplary embodiment, the feed link 52 can be flexible toeliminate the need to calibrate the clip advancing assembly and the clipforming assembly. In particular, the feed link 52 allows the trigger 16to continue moving toward a closed position even after the feed bar 38and feed bar coupler 50 are in a distal-most position, and it providessome freedom to the clip forming and clip advancing assemblies. In otherwords, the trigger 16 is pliant relative to the feed bar 38 duringclosure of the trigger.

The particular stiffness and strength of the feed link 52 can varydepending on the configuration of the clip advancing assembly and theclip forming assembly, but in one exemplary embodiment the feed link 52has a stiffness that is in the range of 75 to 110 lbs per inch, and morepreferably that is about 93 lbs per inch (as measured at the interfacebetween the link 52 and the feed bar coupler 50), and it has a strengthof that is in the range of 25 lbs and 50 lbs, and more preferably thatis about 35 lbs. The feed link 52 can also be formed from a variety ofmaterials, including a variety of polymers, metals, etc. One exemplarymaterial is a glass-reinforced polyetherimide, but a number ofreinforced thermoplastics could be used, including glass reinforcedliquid-crystal polymers, glass-reinforced nylons, and carbon-fiberreinforced versions of these and similar thermoplastics.Fiber-reinforced thermoset polymers such as thermoset polyesters couldalso be used. Feed link 52 could also be fabricated from a metal, suchas spring steel to achieve the desired combination of limitedflexibility and controlled strength.

FIGS. 17A-17D illustrate the exemplary clip advancing assembly in use.FIG. 17A shows an initial position, wherein the trigger 16 is resting inan open position, the feed bar coupler 50 and feed bar 38 are in aproximal-most position, and the feed link 52 extends between the triggerinsert 48 and the feed bar coupler 50. As previously discussed, in theinitial open position the protrusion 86 on the feed bar 38 in positionedin the proximal end of the elongate slot 88 in the jaw retainer shaft28. A first biasing member, e.g., spring 120, is coupled to the triggerinsert 48 and the housing 12 to maintain the trigger insert 48 andtrigger 16 in the open position, and a second biasing member, e.g.,spring 122, extends between a shaft coupler 124, which rotatably matesthe shaft 18 to the housing 12, and the feed bar coupler 50 to maintainthe feed bar coupler 50 and feed bar 38 in the proximal-most position.

When the trigger 16 is actuated and moved toward the closed position,i.e., toward the stationary handle 14, to overcome the biasing forcesapplied by the springs 120, 122, the trigger insert 48 begins to pivotin a counter-clockwise direction, as shown in FIG. 17B. As a result, thefeed link 52 is forced to pivot in a counter-clockwise direction,thereby moving the feed bar coupler 50 and feed bar 38 in a distaldirection. The protrusion 86 on the feed bar 38 thus moves distallywithin the elongate slot 88 in the jaw retainer shaft 28, therebyadvancing the feeder shoe 34 and the clips 36 disposed within the cliptrack. Spring 120 is extended between the housing and the trigger insert48, and spring 122 is compressed between the feed bar coupler 50 and theshaft coupler 124.

As the trigger 16 is further actuated and the trigger insert 48continues to pivot, the feed bar coupler 50 and feed bar 38 willeventually reach a distal-most position. In this position, theprotrusion 86 on the feed bar 38 will be positioned at the distal end ofthe slot 88 in the jaw retainer shaft 28 and a clip will be positionedbetween the jaws 20, as previously discussed. Spring 122 will be fullycompressed between the shaft coupler 124 and the feed bar coupler 50,and the feed link 52 will flex, as shown in FIGS. 17C and 17D. As thefeed link 52 flexes, and more preferably once the feed link 52 fullyflexed, the clip forming assembly will be actuated to close the jaws 20.The feed link 52 will remain flexed during actuation of the clip formingassembly, e.g., the second stage of actuation, such that the triggerinsert 48 is pliant relative to the clip advancing assembly, and inparticular the feed bar 38.

An exemplary clip forming assembly of the housing 12 is shown in moredetail in FIGS. 18-20. In general, the clip forming assembly is disposedwithin the housing 12 and it is effective to move the push rod 44 andcam 42 relative to the jaws 20 to move the jaws 20 to a closed positionand thereby crimp a clip positioned therebetween. While the clip formingassembly can have a variety of configurations, the illustrated exemplaryclip forming assembly includes a closure link roller 54 that is slidablycoupled to the trigger insert 48, a closure link 56 that is adapted tocouple to the closure link roller 54, and a closure coupler 58 that isadapted to couple to the closure link 56 and to the push rod 44.

FIG. 18 illustrates the closure link roller 54 in more detail and, asshown, the closure link roller 54 includes a central shaft 54 a havingsubstantially circular flanges 54 b, 54 c formed adjacent to the opposedterminal ends thereof. The central shaft 54 a can be adapted to sitwithin the second recess 110 in the trigger insert 48 such that theflanges 54 b, 54 c are received on opposed sides of the trigger insert48. The central shaft 54 a can also be adapted to mate to opposed arms126 a, 126 b of the closure link 56 to position the arms on opposedsides of the trigger insert 48.

An exemplary embodiment of a closure link 56 is shown in more detail inFIG. 19, and as shown it has opposed arms 126 a, 126 b that are spaced adistance apart from one another. Each arm 126 a, 126 b includes aproximal end 128 a, 128 b that is adapted to engage the central shaft 54a of the closure link roller 54, and a distal end 130 a, 130 b that isadapted to mate to a closure coupler 58 for coupling the closure linkroller 54 and closure link 56 to the push rod 44. In an exemplaryembodiment, the proximal end 128 a, 128 b of each arm 126 a, 126 b isadapted to pivotally mate to the closure link roller 54, and thus thearms 126 a, 126 b can include, for example, hook-shaped members 132 a,132 b formed thereon for engaging the central shaft 54 a. Thehook-shaped members 132 a, 132 b extend in opposite directions tofacilitate engagement between the closure link 56 and the closure linkroller 54. The distal end 130 a, 130 b of the arms 126 a, 126 b can bemated to one another, and they can include a lumen 134 extendingtherethrough for receiving a shaft that is adapted to pivotally mate theclosure link 56 to the closure coupler 58. A person skilled in the artwill appreciate that a variety of other techniques can be used to matethe closure link 56 to the closure link roller 54 and the closurecoupler 58.

An exemplary closure coupler 58 is shown in more detail in FIG. 20A, andas shown it includes a proximal portion 58 a having two arms 136 a, 136b with lumens 138 a, 138 b extending therethrough and adapted to bealigned with the lumen 134 in the closure link 56 for receiving a shaftto mate the two components. The closure coupler 58 can also include adistal portion 58 b that is adapted to mate to the proximal end 44 a ofthe push rod 44 (FIG. 9). In an exemplary embodiment, the closurecoupler 58 includes a cut-out 59 (FIGS. 20B and 20C) formed therein andhaving a shape that is adapted to seat the proximal end 44 a of the pushrod 44. The distal portion 58 b of the closure coupler 58 can also beconfigured to receive a portion of the feed bar coupler 50 when thetrigger 16 is in the open position. A person skilled in the art willappreciate that a variety of other mating techniques can be used to matethe closure coupler 58 to the push rod 44, and that the closure coupler58 and the push rod 44 can optionally be integrally formed with oneanother.

In other exemplary embodiments, shown in FIGS. 20B and 20C, a biasingmember can be disposed within the cut-out 59 to bias the push rod 44 ina distal direction. Such a configuration will prevent accidental releaseof a clip from the jaws, particularly during the early stages ofclosure, if the user eases-up on the trigger 16. In particular, whilethe anti-backup mechanism, discussed in more detail below, can beadapted to prevent the trigger 16 from opening until the trigger 16reaches a predetermined position, the anti-backup mechanism may allowsome minor movement of the trigger 16. Thus, in the event a usereases-up on the trigger 16 and minor opening of the trigger 16 occurs,the biasing member will bias the push rod 44 in a distal direction,thereby maintaining the push rod 44 in a substantially fixed position.While a variety of biasing members can be used, in the embodiment shownin FIG. 20B, the biasing member is a cantilevered beam 61 that ispositioned between the proximal end 44 a of the push rod 44 and the backwall of the recess 59 to bias the push rod 44 distally. The cantileveredbeam 61 can be formed from a shape memory material, such as Nitinol,that allows the beam 61 to flex or flatten when a proximally-directedforce is applied thereto. The beam 61 can also be formed from a varietyof other materials, such as spring steel or reinforced polymers, andmore than one beam can be used. FIG. 20C illustrates another embodimentof a biasing member which is in the form of a coil or other type ofspring 63. As shown, the spring 63 is disposed between the proximal end44 a of the push rod 44 and the back wall of the recess 59 to bias thepush rod 44 distally. The spring 63 is adapted to compress when aproximally-directed force is applied thereto. A person skilled in theart will appreciate that a variety of other biasing members can be used,including elastomeric compression members.

In use, referring back to FIGS. 17A-17D, as the trigger 16 is initiallymoved from the open position toward the closed position, the closurelink roller 54 will roll within the recess 110 in the trigger insert 48.Once the feed bar 38 and feed bar coupler 50 are in the distal-mostposition, as shown in FIG. 17C, further actuation of the trigger 16 willcause the recess 110 in the trigger insert 48 to engage the closure linkroller 54 forcing it to pivot with the trigger insert 48, as shown inFIG. 17D. As a result, the closure coupler 58 will move distally,thereby causing the push rod 44 to move distally. As the push rod 44advances distally, the cam 42 is advanced over the jaws 20 to close thejaws 20 and crimp the clip positioned therebetween. The trigger 16 canoptionally be partially closed to only partially close the jaws 20 andthus partially crimp a clip disposed therebetween. Exemplary techniquesfor facilitating selective full and partial closure of the clip will bediscussed in more detail below. Once the clip is applied, the trigger 16can be released thereby allowing spring 120 to pull the trigger insert48 back to its initial position, and allowing spring 122 to force thefeed bar coupler 50 and feed bar 38 back to the proximal position. Asthe trigger insert 48 returns to its initial position, the closure linkroller 54 is moved back to its initial position as well, thereby pullingthe closure link 56, closure coupler 58, and push bar 44 proximally.

The surgical clip applier 10 can also include a variety of otherfeatures to facilitate use of the device 10. In one exemplaryembodiment, the surgical clip applier 10 can include an anti-backupmechanism for controlling movement of the trigger 16. In particular, theanti-backup mechanism can prevent the trigger 16 from opening during apartial closing stroke. However, once the trigger reaches apredetermined position, at which point the clip positioned between thejaws can be partially crimped, the anti-backup mechanism can release thetrigger allowing the trigger to open and release the clip or to close tofully crimp the clip, as may be desired by the user.

FIGS. 21A and 21B illustrate one exemplary embodiment of an anti-backupmechanism in the form of a ratchet. As shown, the ratchet includes a setof teeth 112 formed on the trigger insert 48, and a pawl 60 that isadapted to be rotatably disposed within the housing 12 and positionedadjacent to the trigger insert 48 such that closure of the trigger 16and pivotal movement of the trigger insert 48 will cause the pawl 60 toengage the teeth 112. The teeth 112 can be configured to preventrotation of the pawl 60 until the pawl 60 reaches a predeterminedposition, at which point the pawl 60 is free to rotate, thereby allowingthe trigger 16 to open or close. The predetermined position preferablycorresponds to a position at which the jaws 20 are partially closed. Inan exemplary embodiment, as shown, the teeth 112 include a first set ofteeth 112 a, e.g., ten teeth, having a size that prevents rotation ofthe pawl 60 relative thereto, thus preventing the trigger 16 fromopening when the pawl 60 is engaged with the first set 112 a of teeth112. The teeth 112 can also include a final or terminal tooth, referredto as a tock tooth 112 b, that has a size that allows the pawl 60 torotate relative thereto when the pawl 60 is engaged with the tock tooth112 b. In particular, the tock tooth 112 b preferably has a size that issubstantially greater than the size of the first set of teeth 112 a suchthat a relatively large notch 140 is formed between the first set ofteeth 112 a and the tock tooth 112 b. The notch 140 has a size thatallows the pawl 60 to pivot therein, thus allowing the pawl 60 to beselectively moved beyond the tock tooth 112 b or back toward the firstset of teeth 112 a. A person skilled in the art will appreciate that thetock tooth 112 b can have the same size or a smaller size than the firstten teeth 112 a while still providing a notch 140 formed therebetweenthat allows the pawl 60 to pivot therein.

FIGS. 22A-22D illustrates the ratchet mechanism in use. When the trigger16 is initially moved toward a closed position, as shown in FIG. 22A,the pawl 60 will engage the first set of teeth 112 a thereby preventingthe trigger 16 from opening. Further actuation of the trigger 16 willcause the pawl 60 to advance past the first set of teeth 112 a until thepawl 60 reaches the notch 140 next to the tock tooth 112 b. Once thepawl 60 reaches the tock tooth 112 b, at which point the jaws 20 arepartially closed due the partial distal movement of the cam 42 over thejaws 20, the pawl 60 is free to rotate thereby allowing the trigger 16to open or close, as may be desired by the user. FIG. 22C illustratesthe trigger 16 in a fully-closed position, and FIGS. 22D and 22Eillustrate the trigger 16 returning to the open position.

The ratchet mechanism can also be configured to emit an audible soundthat indicates the position of the jaws 20. For example, a first soundcan be emitted when the pawl 60 engages the first set of teeth 112 a,and a second, different sound, e.g., a louder sound, can be emitted whenthe pawl 60 engages the tock tooth 112 b. As a result, when the trigger16 reaches the predetermined position at which the pawl 60 is engagedwith the tock tooth 112 b, the sound indicates to the user that the jaws20 are in the partially closed position. The user can thus release thetrigger 16 to release a partially closed clip, or they can fully closethe trigger 16 to fully close the clip.

In another exemplary embodiment, the surgical clip applier 10 caninclude an overload mechanism that is adapted to prevent overload of aforce applied to the jaws 20 by the trigger 16. Typically, duringapplication of a surgical clip, a certain force is required to close thejaws 20 and crimp the clip around the tissue positioned therebetween. Asthe forming process proceeds and the clip is at least partially closed,the force required to continue closing the jaws 20 around the clipsignificantly increases. Accordingly, in an exemplary embodiment, theoverload mechanism can have a resistance that correlates to the forcerequired to close the jaws 20. In other words, the resistance of theoverload mechanism can increase as the force required to close the jaws20 increases. The resistance is, however, preferably slightly greaterthan the force required to close the jaws 20 to prevent accidentalactuation of the overload mechanism. As a result, if the jaws 20 areprevented from closing when the trigger 16 is initially actuated, theforce required to overcome the resistance of the overload mechanism isrelatively low. This is particularly advantageous as the jaws 20 aremore susceptible to being deformed when they are open or only partiallyclosed. The overload mechanism will actuate more readily in the earlystages of clip formation to prevent deformation of the jaws. Conversely,when the jaws 20 are substantially closed, the resistance is relativelyhigh such that the overload mechanism can only be actuated uponapplication of a significant force applied to the jaws 20.

FIG. 23A illustrates one exemplary embodiment of an overload mechanism62, showing an exploded view. In general, the overload mechanism caninclude an overload housing 64 formed from two halves 64 a, 64 b andcontaining a profile link 66, a toggle link 68, a pivot link 70, and abiasing assembly 72. The biasing assembly 72 can include a spring post150 that is coupled to the housing 64 and that includes a bore extendingtherethrough for receiving a plunger 154. A spring 152 is disposedaround the spring post 150, and the plunger 154 extends through thespring post 150 and includes a head 154 a formed thereon that is adaptedto abut against the spring 152. The pivot link 70 can be generallyL-shaped and it can be coupled to the housing 64 by a pivot pin 156extending therethrough. A proximal end 70 a of the pivot link 70 cancontact the head 154 a of the plunger 154, and a distal end 70 b of thepivot link 70 can be pivotally coupled to the toggle link 68 by a pivotpin 166. The toggle link 68, in turn, can be coupled to the profile link66, which can be slidably and pivotally positioned within the housing 64adjacent to an opening 64 d formed in the housing. Pivotal movement ofthe profile link 66 within the housing 64 can be achieved by, forexample, a pivot pin 158 that extends through the profile link 66 and isthat disposed within a first slot 160 a (only one slot is shown) formedin each half 64 a, 64 b of the housing 64, and slidable movement of theprofile link 66 within the housing 64 can be achieved by, for example,opposed protrusions 168 a, 168 b formed on the profile link 66 that arereceived within a second slot 160 b (only one slot is shown) formed ineach half 64 a, 64 b of the housing 64.

In use, the profile link 66 can be adapted to receive a force from theclip forming assembly and to counter the force with the resistance ofthe biasing assembly 72. In particular, the overload mechanism 62 usesthe spring 152 along with the toggle link 68 and pivot link 70 to biasthe profile link 66 from either rotating about the pivot pin 158 orsliding against the housing 64. For the rotational aspect, the forceexerted by the compressed spring 152 is transferred through the togglelink 68 and pivot link 70, such that a rotational moment is applied tothe profile link 66 against the housing 64. Thus this assembly causesthe profile link 66 to resist rotation with respect to the housing 64.If the moment generated by a radial load from the closure link roller 54against the profile link 66 exceeds the moment of the pivot link 70 andtoggle link 68, the profile link 66 begins to rotate, buckling thetoggle link 68 and causing the pivot link 70 to further compress thespring 152. For the sliding aspect, the pivot link 70, toggle link 68,and profile link 66 are aligned such that the sliding force (resistanceto slide) is the force required to buckle the toggle link 68 and pivotlink 70. If the radial load from the closure link roller 54 against theprofile link 66 exceeds the buckling force of the linkages, then thepivot link 70 further compresses the spring 152 as the profile link 66slides proximally.

This is shown in more detail in FIGS. 23B-23C, and as shown the opening64 d in the housing 64 allows the closure link roller 54 of the clipforming assembly to roll against the profile link 66. As a result, whenthe trigger 16 is actuated and moved toward the closed position, theclosure link roller 54 applies a force to the profile link 66. Theresistance of the overload spring 152 will, however, maintain theprofile link 66 in a substantially fixed position unless the forceapplied by the closure link roller 54 increases to a force that isgreater than the resistance, e.g., a threshold force. This can be causedby, for example, a foreign object positioned between the jaws 20 or whenthe jaws 20 are fully closed with the clip and vessel, duct, shunt, etc.therebetween. When the jaws 20 cannot be further closed, the forceapplied to the closure link roller 54 from the closing motion of thetrigger 16 will be transferred to the profile link 66, which will thenpivot and slide within the housing 64, thereby causing the pivot link 70to pivot, which forces the plunger 154 to compress the overload spring152.

As previously noted, the force required to actuate the overloadmechanism can correlate to the force required to close the jaws 20,which increases as the trigger 16 is moved to the closed position. Thiscan be achieved due to the configuration of the profile link 66. Inparticular, when the closure link roller 54 first comes into contactwith the profile link 66 and is thus in a lower position, the profilelink 66 can pivot within the housing 64, as shown in FIG. 23B. As theclosure link roller 54 moves upward along the profile link 66, the forcerequired to overcome the resistance of the overload mechanism increasesbecause the profile link 66 must slide within the housing 64, as shownin FIG. 23C. The force required to pivot the profile link 66 can be lessthan the force required to slide the profile link 66. Accordingly, ifthe jaws 20 are prevented from being closed, e.g., by a foreign object,as the trigger is initially actuated, a minimal force will be requiredto cause the closure link roller 54 to transfer the force to the lowerportion of the profile link 66 causing the profile link 66 to pivot.When the jaws 20 are substantially closed and the trigger 16 is almostfully actuated, a significant amount of force is required to cause theclosure link roller 54 to transfer the force to the upper portion of theprofile link 66 causing the profile link 66 to slide within the housing64 to overcome the resistance of the overload spring 152. While theamount of force required to actuate the overload mechanism can begreater than and can increase relative to the amount of force requiredto close the jaws 20, the force is preferably only slightly greater thanthe force required to close the jaws 20 to prevent deformation or otherdamage to the jaws 20. A person skilled in the art will appreciate thatthe resistance can be adjusted based on the force necessary to close thejaws 20.

The profile link 66, and in particular the distal-facing surface 66 s ofthe profile link 66, can also have a shape that facilitates correlationbetween the force required to actuate the overload mechanism and theforce required to close the jaws 20. For example, where the forcerequired to close the jaws 20 increases at a linear rate, thedistal-facing surface 66 s of the profile link 66 can be planar toprevent the profile link 66 from interfering with movement of theclosure link roller 54 there over, and to allow a linear force to beapplied to the trigger 16 to close the jaws 20. Conversely, where theforce required to close the jaws 20 is non-linear as the trigger 16 ismoved to the closed position, the profile link 66 can have a non-linearshape that corresponds to the non-linear force. Such a configurationwill prevent the forces required to close the cam 42 (FIG. 8) frombecoming too high.

By way of non-limiting example, the force required to close the jaws 20can be non-linear due to the shape of the recess 104 in the cam 42 thatis adapted to push the jaw members 96 a, 96 b toward one another. Asshown in FIG. 8, the recess 104 can have a curved configuration suchthat the force will vary as the cam 42 passes over the jaw members 96 a,96 b. The profile link 66 can therefore having a corresponding curveddistal-facing surface such that the force will also vary as the closurelink roller 54 passes there over. As shown in FIGS. 23A and 23B, theprofile link 66 is curved such that the lower portion of the profilelink 66 is substantially convex and the upper portion of the profilelink 66 is substantially concave. A person skilled in the art willappreciate that the profile link 66 can have a variety of other shapes,and that a variety of other techniques can be used to optimize the forcenecessary to close the jaws 20 and the force necessary to actuate theoverload mechanism.

A person skilled in the art will also appreciate that the overloadmechanism can have a variety of other configurations. By way ofnon-limiting example, FIG. 23D illustrates an overload mechanism that isin the form of a cantilevered beam 170 for receiving a force applied bythe closure link roller 54. The beam 170 can have a substantially curvedmember 172 with a bracket 174 coupled to one end thereof. The curvedmember 172 can have a bending moment that, when loaded with a forcegreater then the bending moment, buckles to assume a low rigiditycondition. The bracket 174 can provide more rigidity to the curvedmember 172 such that the bending moment increases adjacent to thebracket 174. In use, the beam 170 can be loaded within the housing 12 ofthe clip applier 10 such that the closure link roller 54 contacts theconcave surface, and the beam 170 can be positioned at an angle suchthat the closure link roller 54 is farther away from the beam when thetrigger 16 is initially actuated, and the closure link roller 54 becomescloser to the beam as the trigger 16 moves to the closed position. As aresult, the resistance to buckling will increase as the closure linkroller 54 moves thereof and the trigger 16 of the clip applier is movedto the closed position. Although not shown, multiple beams couldoptionally be used in a stacked fashion and the terminal or free end ofthe beam(s) could be contoured to tailor the buckling load at aparticular point along the length of the beam.

In another exemplary embodiment, the surgical clip applier 10 caninclude a clip quantity indicator for indicating the number of clipsremaining in the device 10. While various techniques can be used toindicate the quantity of clips remaining, FIGS. 24A-25 illustrate oneexemplary embodiment of a clip quantity indicator having an indicatorwheel 74 and an indicator actuator 76.

The indicator wheel 74 is shown in detail in FIGS. 24A and 24B, and asshown it has a generally circular or cylindrical shape that defines acentral axis Y about which the wheel 74 is adapted to rotate. The wheel74 includes teeth 142 formed therearound and adapted to be engaged bythe indicator actuator 76, and an indicator member 144. The indicatormember 144 can have a variety of configurations, but in an exemplaryembodiment the indicator member 144 is in the form of a contrastingcolor pad having a color, e.g., orange, red, etc., that differs from theremainder of the indicator wheel 74.

FIG. 25 illustrates the exemplary indicator actuator 76 in more detail.The actuator 76 is adapted to be slidably disposed within the housing 12and to couple to the feed link coupler 50 and move as the feed barcoupler 50 and feed bar 38 are moved. Accordingly, the indicatoractuator 76 can include a protrusion 146, only a portion of which isshown, formed on an inferior surface thereof for extending into therecess 50 f formed between the circular flanges 50 d, 50 e on the feedbar coupler 50. The protrusion 146 allows the indicator actuator 76 tobe engaged by the feed bar coupler 50 and moved therewith. The indicatoractuator 76 can also include an engagement mechanism 148 formed thereonand adapted to engage the teeth 142 formed on the indicator wheel 74. Asshown in FIG. 25, the engagement mechanism 148 on the indicator actuator76 is in the form of an arm having a tab formed on the end thereof forengaging the teeth 142.

In use, the indicator wheel 74 is rotatably disposed within the housing12, as shown in FIGS. 26A-26B, and the indicator actuator 76 is slidablydisposed within the housing 12 such that the engagement mechanism 148 ispositioned adjacent to the indicator wheel 74 and the protrusion 146extends into the feed bar coupler 50. The housing 12 includes a window12 a formed therein for providing visual access to the indicator wheel144. As the trigger 16 is moved to the closed position and the feed barcoupler 50 is moved distally, the indicator actuator 76 will movedistally with the feed bar 38 and feed bar coupler 50. As a result, theengagement mechanism 148 on the indicator actuator 76 will engage theteeth 142 on the indicator wheel 74, thereby causing the wheel 74 torotate as a clip is advanced into the jaws 20. Each time the trigger 16is actuated to advance a clip 20 into the jaws 20, the indicatoractuator 74 rotates the indicator wheel 76. When the clip supply has twoor three clips left, the contrasting color pad 144 on the indicatorwheel 74 will begin to appear in the window 12 a formed in the housing12, thereby indicating to the user that only a few clips remain. Thecontrasting color pad 144 can be adapted to occupy the entire window 12a when the clip supply is depleted.

In another exemplary embodiment, the indicator wheel 74 can include ananti-backup mechanism that is adapted to prevent the indicator wheel 74from rotating in a reverse direction, e.g., a counter-clockwisedirection, after being advanced. While the anti-backup mechanism canhave a variety of configurations, in the embodiment shown in FIG. 24Bthe indicator wheel 74 includes opposed arms 73 a, 73 b that extendsubstantially parallel to the axis Y. Each arm 73 a, 73 b has a pawl 75a, 75 b formed on a distal-most end thereof that is adapted to engagecorresponding teeth formed on the housing 12. While not shown, thecorresponding teeth can be formed within a circular protrusion formed onan inner portion of the housing 12 adjacent to the window 12 a. When theindicator wheel 74 is disposed within the housing 12, the arms 73 a, 73b extend into the circular protrusion formed around the innercircumference thereof. As a clip is applied and the indicator wheel 74is rotated, the arms 73 a, 73 b can deflect over the teeth in thehousing to move to the next position. When the indicator actuator 76slides proximally to return to its initial position, the arms 73 a, 73 bwill engage the teeth in the housing to prevent the indicator wheel 74from rotating in a reverse direction, i.e., returning to the previousposition. A person skilled in the art will appreciate that a variety ofother techniques can be used to prevent backup of the indicator wheel74.

As previously mentioned, the surgical clip applier 10 can be used toapply a partially or fully closed clip to a surgical site, such as avessel, duct, shunt, etc. In laparoscopic and endoscopic surgery, asmall incision is made in the patient's body to provide access to asurgical site. A cannula or access port is typically used to define aworking channel extending from the skin incision to the surgical site.Often during surgical procedures it is necessary to cease blood flowthrough the vessels or other ducts, and some procedures may require theuse of a shunt. A surgical clip can thus be used to crimp the vessel orto secure the shunt to the vessel. Accordingly, a surgical clip applier,such as clip applier 10, can be introduced through the cannula orotherwise introduced into the surgical site to position the jaws 20around the vessel, shunt, or other duct. The tissue stop 46 canfacilitate positioning of the jaws 20 around the target site. Thetrigger 16 can then be actuated to cause a clip to be advanced betweenthe jaws and positioned around the target site, and to cause the jaws 20to close to crimp the clip. Depending on the intended use of the clip,the trigger 16 can be partially actuated, as indicated by the audiblesound of the pawl 60 reaching the tock tooth 112 b, or it can be fullyactuated. The trigger 16 is then released to release the partially orfully closed clip, and the procedure can be repeated if necessary toapply additional clips.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

What is claimed is:
 1. An overload mechanism for use with a surgicaldevice, comprising: a force-receiving member pivotally and slidablydisposed in a housing and having a surface configured to receive aforce, the surface having a first end and an opposed second end; and abiasing assembly pivotally and slidably disposed in the housing, thebiasing assembly including a biasing element configured to resistmovement of the force-receiving member, the resistance to movementincreasing as the force applied to the surface moves from the first endof the surface to the second end of the surface, and a pivoting elementdisposed within the housing and coupled between the force-receivingmember and the biasing element such that the pivoting element is adaptedto transfer a force applied to the force-receiving member to the biasingelement to overcome the resistance.
 2. The overload mechanism of claim1, wherein the force-receiving member is disposed adjacent to an openingformed in the housing.
 3. The overload mechanism of claim 1, wherein thepivoting element comprises a toggle link that is pivotally coupled tothe force-receiving member, and a pivot link that is pivotally coupledto the toggle link and that is adapted to apply a force to the biasingelement upon pivotal movement thereof.
 4. The overload mechanism ofclaim 1 wherein the force-receiving surface includes a first portionthat is adapted to receive a force for pivotally moving theforce-receiving member within the housing, and a second portion that isadapted to receive a force for slidably moving the force-receivingmember within the housing.
 5. The overload mechanism of claim 4, whereinthe force-receiving surface is curved to provide a non-linearresistance.
 6. The overload mechanism of claim 1, wherein the biasingelement comprises a spring disposed around a spring post, and a plungerslidably disposed relative to the spring post and having a head formedthereon and adapted to compress the spring upon slidable movement of theplunger toward the spring post.
 7. The overload mechanism of claim 1,wherein both the force-receiving member and the biasing assembly aredisposed within the housing in both initial position and finalpositions.
 8. The overload mechanism of claim 1, wherein theforce-receiving surface has a substantially convex portion and asubstantially concave portion.
 9. An overload assembly for use with asurgical device, comprising: an overload mechanism having aforce-receiving member that includes a non-linear surface having asubstantially convex portion and a substantially concave portion, theforce-receiving member being adapted to resist displacement in responseto a force applied thereto, the resistance increasing as the forceapplied thereto moves from a first end to a second opposed end of theforce-receiving member; and an actuation mechanism adapted to actuatejaws formed on a distal end of a surgical device, the actuationmechanism having a portion that is adapted to apply a force to andtranslate across the substantially convex and substantially concaveportions of the non-linear surface of the force-receiving member fromthe first end to the second end during actuation of the actuationmechanism to apply a fastener into tissue.
 10. The overload assembly ofclaim 9, wherein the actuation mechanism is adapted to apply anon-linear force to the force-receiving member that increases as theportion of the actuation mechanism translates across the force-receivingmember, the resistance of the force-receiving member correlating to thenon-linear force of the actuation mechanism.
 11. The overload assemblyof claim 10, wherein the actuation mechanism includes a camming assemblyhaving a non-linear camming surface that is adapted to produce thenon-linear force when the actuation mechanism is actuated.
 12. Theoverload assembly of claim 10, wherein the non-linear surface is adaptedto receive the non-linear resistance that correlates to the non-linearclosing force of the actuation mechanism.
 13. The overload assembly ofclaim 9, wherein the force-receiving member comprises a rigid memberthat is slidably and pivotally disposed within a housing.
 14. Theoverload assembly of claim 9, wherein the force-receiving membercomprises a flexible band that is adapted to deform when the forceapplied thereto is greater than the resistance.
 15. The overloadassembly of claim 9, wherein the non-linear surface is formed on adistal end of a rigid member that is slidably and pivotally disposedwithin a housing in both an initial position and a final position. 16.The overload assembly of claim 9, wherein the substantially convexportion of the non-linear surface is located at the first end of theforce-receiving member, and the substantially concave portion of thenon-linear surface is located at the second opposed end of theforce-receiving member.